1. Field of the Invention
The present invention relates to an aqueous ink, specifically, relates to a recording method and a recording device using an ink jet recording system; further the aqueous ink suitable for an ink jet recording method (an image forming method or a recording method); and an ink jet recording method, an ink cartridge, a recording unit, an ink jet recording apparatus and an image forming method using the aqueous ink.
2. Related Background Art
Up to now, as an ink for a writing implement (a fountain pen, a marking pen and a water-based ball-point pen) and an ink for an ink jet printer, an ink including a pigment which is a colorant capable of providing a recorded matter having high print density and superior fastness has been proposed.
Particularly in resent years, a detailed research has been performed from various viewpoints including the composition and physical properties of the ink, for the purpose of obtaining an adequate document on plain paper such as copying paper, writing paper, a note book, letter paper, bond paper and a continuous business form, which are generally used in an office.
For instance, some patents propose a pigment aqueous ink containing carbon black and a dispersing agent, as a pigment ink having the above described property (see Japanese Patent Application Laid-Open No. S61-283875 and Japanese Patent Application Laid-Open No. S64-6074 for instance).
Another patent points out a technical problem that when an ink containing carbon black as pigment and containing a dispersing agent is used for an ink in an ink jet recording apparatus, the ink is unstably ejected and adequate print density is not obtained, and proposes a pigment aqueous ink containing so called self-dispersion carbon black which can be dispersed without using a dispersing agent, as an ink for solving such a problem (see Japanese Patent Application Laid-Open. No. H8-3498 for instance).
When using the above described pigment aqueous ink as a black ink, and recording a color image in combination with other color inks (for instance, at least one ink selected from a magenta ink, a cyan ink, a yellow ink, a red ink, a green ink and a blue ink), a problem described below occurs. Specifically, such a phenomenon as boundary between a black image and a color image formed on a recording medium smears, or the inks are non-uniformly mixed to deteriorate image quality (hereafter called “bleeding”) occurs. Other patents propose a method for improving the permeability of ink to a recording medium by adding a surfactant to the ink, as means for inhibiting the bleeding, in other words, for improving bleeding resistance (see Japanese Patent Application Laid-Open No. S55-65269 for instance), or a method for improving a drying rate of the ink applied to the recording medium, by mainly using a volatile solvent for the solvent of the ink (see Japanese Patent Application Laid-Open No. S55-66976 for instance). Furthermore, other patents propose a method for improving not only bleeding resistance but also character quality and print density, by using a black ink containing a self-dispersion carbon black and a particular salt (see Japanese Patent Application Laid-Open No. 2000-198955 and Japanese Patent Application Laid-Open No. 2002-80763, for instance).